Clinical History, Examination and Blood Test Results

  • Discussion case 4 presents an 81-year old gentleman with a background of bilateral ASR XL metal on metal hip replacements implanted in 2007. These were revised, the right in 2015 and the left in 2016 due to adverse reactions to metal debris.

  • He was referred to our service due to worsening stiffness, pain and oozing from the right hip. The right hip wound never healed successfully after the revision procedure, and at presentation he was controlling the oozing with a colostomy bag over the wound.

  • On examination he mobilised with the aid of a walking stick. He was Trendelenburg negative on both sides. He had a good ROM in his left hip. He had reduced active ROM in the right hip, with straight leg raise restricted to 20 degrees due to pain. Passive movements were reasonable. He had a normal knee examination with intact foot pulses and foot sensation.

  • This patient had the following investigations done;

    • Blood inflammatory markers – CRP 63

    • Right hip aspiration – Grew enterococcus and Staphylococcus lugdunensis

    • MRI and CT pelvis – See below

    • Bone infection MDT – Recommended a 2 stage procedure


Imaging Results

PRE-OP RADIOGRAPH

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PRE-OP MRI

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This is the pre-operative AP radiograph. No major osteolysis can be seen with the plain x-ray. Soft tissue damage is visualised with the MRI.

There are significant fluid collections around both hips with significant abductor muscle destruction. The fluid collection around the right hip extends to the wound.

 

PRE-OP CT

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The CT scan demonstrates good remaining bone stock in the pelvis.

 

Diagnosis

  • Right prosthetic hip infection with Enterococcus and Staphylococcus lugdunensis on a background of abductor wasting due to an adverse reaction to metal debris.


Treatment Stage 1

  • Stage 1 of treatment was removal of the well-fixed components and the implantation of a cemented temporary spacer.

  • Intraoperatively;

    • Posterior approach

      • The sinuses were excised

    • Fluid and tissue samples were obtained and sent for microbiology histology

    • Ceramic on polyethylene bearing in situ with well-fixed components

    • Significant abductor loss noted – 50% inferiorly

    • Femoral stem extraction;

      • Midas rex pencil reamer

      • Flexible osteotomes

      • Corail stem extractor

    • Acetabular cup extraction and screw removal

    • Wash with savlon and normal saline

    • C-stem cemented femoral spacer inserted with a metal head and polyethylene acetabular liner  

      • Cement + Vancomycin and Gentamicin

    • Stable joint and good length

    • Closed by layers – Ethibond, vicryl and clips

 

INTRAOPERATIVE VIDEO

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Imaging Outcomes Stage 1

POST-OP RADIOGRAPHS

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These post-operative plain film radiographs demonstrate the cemented C-stem spacer in situ.

 

Treatment Stage 2

  • 8-weeks after stage 1, stage 2 was completed to revise the spacer.

  • Intraoperatively;

    • Posterior approach through the old incision

    • Spacer removed

    • Specimens sent for microbiology and histology

    • Socket reamed to 64mm to bleeding bone

    • New acetabular cup implanted with 3 good screws

    • Stem rasped to 14mm and new Corail stem implanted

    • Bearing consisted of;

      • +4 liner lipped at 10 degrees

      • 36mm poly

      • 36+8.5 ceramic head

    • This was stable and a good length was achieved

    • Washed with savlon and normal saline

    • Close


Imaging Outcomes Stage 2

POST-OP RADIOGRAPHS

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6-WEEK POST-OP RADIOGRAPHS

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The post-operative radiographs after the second stage of the procedure show adequate positioning of the right stem and acetabular shell.

The post-operative radiographs at 6-weeks follow-up show no subsidence of the femoral stem.


Clinical Outcomes

  • At three weeks’ post-op the patient was walking up to three quarters of a mile with the aid crutches. The wound had healed by this point with the plan to continue exercise using a static bike with the aid of a physiotherapist.

  • At later follow up, this gentleman was functioning extremely well with no wound issues despite many months of having to use a colostomy bag to collect pus oozing from the wound.


Learning Points

  • Plan equipment

    • Plan A: removal from the top without osteotomy. Use the following: Midas Rex pencil reamer (more effective than k wires, however beware ease of exiting the femur); flexible osteotomes; extractor with slap hammer.

    • Plan B: extended trochanteric osteotomy. Use standard saw, then reciprocating saw, then midas rex for distal corners, then 2 large osteotomes to lever open the bone. 3 cables will be needed and a trochanteric plate may be needed.